Author Topic: Air Conditioner noise  (Read 27303 times)


  • Guest
Air Conditioner noise
« on: August 08, 2006, 07:03:26 PM »
I recently had an air conditioner installed on my forced air furnace. The noise has increased in the house because the blower fan now runs on high when the A/C is on. We have to turn up the TV when it comes on.

The furnace / A/C is in the hall in a small closet with the return air inlet just below it. Is there a way to sound proof the closet and/or the return air inlet to decrease the noise.

Our contractor that put it in says it is normal for the unit to make more noise.

Thanks for your help.


  • Guest
Re: Air Conditioner noise
« Reply #1 on: August 08, 2006, 11:53:33 PM »
Hello Kens,

To sound proof the closet you would use either MLV or SSP Mat - or a combination of the two.  For info on MLV see

And for info on SSP Mat see chart at top of

Some people simply line the inside walls and ceiling (include inside of door as well) with SSP Mat in 1" thickness (minimum 1/2" thick).  This will absorb and block sound within the contained space.  If there is a great deal of noise within the closet and you want to make sure to block it from transmitting though walls/ceiling/floor then you will want to use a layer of 1/8" MLV (without foam) to the surface and then add the SSP Mat over that.

Remember, the first rule of soundproofing is to place something between the source and the target.  And the closer to the source, the better it works.

To reduce the noise from the return air inlet you can apply SSP Mat directly to the metal - either outside or (if you can get in there) the inside of the inlet.  SSP Mat has been used inside HVAC metal ductwork extensively to quiet noise.



  • Guest
Re: Air Conditioner noise
« Reply #2 on: October 22, 2009, 03:07:22 PM »
I realize this is an old post, but I have almost the same exact problem as the original poster.

My HVAC unit is in a closet where the return-air duct is directly underneath and to the side of the actual unit.  The return air duct faces the living room and is very loud when the A/C is turned on.

There is zero ducting distance from the air-intake to the HVAC unit itself.  In other words, when I open the door to change the filter, I can reach up inside the intake of the HVAC unit if I want to.

Given this situation and the proximity of the intake fan to the actuall vent, it doesn't seem like simply lining the space inside the return air vent would stop much sound from coming out the vent.  Is there anything else I can do to silence the noise coming from this return air vent?

Randy S

  • Guest
Re: Air Conditioner noise
« Reply #3 on: November 03, 2009, 06:37:22 PM »
Ok, why do you contact me directly (my info is below) and we can brain strom an idea how to acheive a baffle system with the limited space you have.
Most likely based on the info you have provided, this will not be easy.